Chronograph Watches: A Glossary of Chronograph Terms You Should Master

A glossary that will help you feel closer to your favorite chronograph

If you're a chronograph fan, we're introducing you to our glossary of chronograph terms, from terms you're sure to already know to movement jargon used by watchmakers.

With a thorough explanation included, you may become even more fascinated with the charm of chronographs.


It has an in-dial that can measure the number of breaths per minute.

Release the chronograph hands and then repeat for five breaths.

When you then stop the hands, it will display the number of breaths per minute.

Aviation Watches

A chronograph made for airline pilots.

A rotating slide rule is built into the outside of the dial.

Albert Piguet

This is the name of the genius watchmaker at Lemania who developed the Cal. 27CHRO C12 (Cal. 321 used in the early Omega Speedmaster models) that appeared in 1942.


It is located between the balance and the escape wheel.

Claw stones (artificial rubies) are set into the ends of the branching arms.

Ankle support

There are also movements that seem to share the same bridge as the escape wheel.

This refers to the bearing of the anchor (lever).


It means precious stones.

They are mainly used as bearings in movements.

The most common type is synthetic ruby, but synthetic sapphire is sometimes used.


This refers to the earthquake-resistant mechanism.

There are several names for it depending on the manufacturer.

It is also called a diamond shock or a parashock.

This refers to the mechanism in which the core of the balance is supported by a spring-loaded hole jewel to prevent the core of the balance wheel from breaking.


It is a small window inside the dial.

At the counter circle.

The three in circle is becoming more common these days.

Three in circle refers to a three-hand design that features a second hand, a 30-minute counter, and a 12-hour counter.

Exotic Dials

This is one of the dial types of Rolex Daytona from the 1960s.

It is known that Paul Newman was a fan of this dial, so it is sometimes called the Paul Newman dial.


This refers to the base movement produced by a manufacturer that specializes in movements.

Or it may refer to the manufacturer itself.

El Primero

This refers to a model equipped by Zenith.

In 1969, we developed the world's first model equipped with an automatic winding chronograph movement.

Rolex's current "Daytona" watches (Ref. 16520, etc.) are equipped with a tuned version of this chronograph movement.

Tuning fork type

It is an electric movement that uses the principle of a resonating tuning fork.

This movement is used in models derived from the Speedmaster, such as the Omega Speed ​​Sonic f300Hz (Ref. 188.0002, manufactured in 1973).

Rotating slide rule

The outer bezel allows you to easily perform calculations such as conversion, multiplication, division, speed, distance, time, ascent, descent, etc.

It is equipped with a Breitling Navitimer.


I'm talking about in-dial.

It refers to the small dial.

A dial with special indications that are stamped or printed on the dial.


It means counting backwards, such as 10, 9, 8...

It is installed in models such as the Omega Speedmaster X-33.

Rack wheel

It is a gear that plays an important role.

Used to wind the mainspring.

It takes a lot of force.

It is designed to fit securely onto the shaft, with the hole in the middle being square.

Square Socket Screw

This is a screw for fixing a ratchet wheel.

They come in a variety of shapes, including domed, chamfered, and even those that resemble a ratchet wheel when tightened.


Apply two or three layers.

This is a rubber gasket that is attached to the crown to improve water resistance.

Coupling clutch

This is a device that brings the transmission wheel and the chronograph runner into contact and releases them in sync with starting and stopping the chronograph.

Cam-operated chronograph

This is a model that uses a cam.

It is used to reset the chronograph hands and the counter hands.

Side set screw

These are the screws used to secure the movement to the case.

There are various shapes.

There are also some that first loosen the bolt and then use a tension rod to secure it in place.

Escape wheel

Together with the anchor it forms the escape mechanism.

This is a very special gear that controls the power of the mainspring.

By coming into contact with the pallet stones in the pallet fork, it converts the rotational motion of the axle train into reciprocating motion in the pallet fork and transmits this to the balance wheel.


An early type of timing device.

You can adjust the time depending on the length of your beard.

By clamping your beard with a beard stick and changing its position, the length of your beard will change.

The vibration is adjusted by touching the balance shaft in the center.


It is inserted into the groove in the center of the Tsuzumi car.

When this meshes with the gear, the tension creates a force in a certain direction.

Crazy car

It is a gear called the winding stem, with the rod with the crown attached passing through a central hole.

This winding stem first rotates the winding wheel, which in turn rotates the crown wheel, which is free relative to the winding stem. The crown wheel rotates the crown wheel, which winds up the mainspring.


This is a movement developed by Seiko.

It was born in 1988 as a movement equipped with an automatic power generation mechanism.

In 1998, the Cal. 9T series for chronographs was released.


This is an earthquake-resistant device.

This is to protect the movement from shocks.

The Valjoux Cal. 727 has been used in all previous Daytona models.

The KIF equipped on this Cal. 727 is the KIF Ultra Reflex.

Caterpillar Belt

It is so named because it resembles the tracks of a tank.

This refers to a triple bracelet made of a stainless steel case.

It has been used in all Speedmaster models released so far.


This is what we call the form of the movement.

Generally, they are identified by numbers such as Cal.0000.


This refers to a movement that uses a quartz oscillator as an oscillation source, invented by the American Marrison in 1927.

Its accuracy is much higher than that of mechanical watches.


This is what we call a watch that has a stopwatch built in.

This is the name given to any watch that has a stopwatch function, whether it is analog or digital.

Chronograph Hands

One lap can measure 60 seconds.

This is the name given to the stopwatch hand located where the center second hand is located in a three-hand watch.

Chronograph Runner

Also known as the driving wheel, it is the fourth gear from the barrel, or also called the fourth wheel.

It rotates once per minute in conjunction with this driving wheel.

The needle on the 30-minute counter is used to check the number of rotations at this time.


It was unveiled to the world at the Basel Fair in 1969.

This refers to the Cal. 11 automatic chronograph movement developed by Heuer, Breitling, and Buren-Hamilton.

This was the first such development in the world.


This refers to a chronograph that has the function of recording the time specified by the user.

It was developed exclusively by Movado.

The bezel has a double structure.

Inside are numbers 1 to 12.

The outside has the numbers 0 to 60 written on it.


It was established in 1951 by the Swiss Watchmaking Association.

It is awarded to movements that have passed tests at an official testing laboratory, which expose them to different temperatures and five different positions for defined periods of time.


This is the main body where the movement is housed.

There are also one-piece types called monocoque types.

Coin Edge

This refers to a grooved decoration that resembles the edge of a coin.

It is applied to the bezel and sides of the case.

From a structural standpoint, it appears to be highly durable.

Incense box

This is the gear that holds the mainspring.

It is also called the first car.

If a mainspring breaks, care is taken to ensure that other parts are not damaged.

It is not built in its bare state.

It uses a barrel that is a container-shaped gear.

Incense box true

It is also called the truest.

This refers to the first shaft of the power source.

Inside is the hook needed to wind the mainspring.

The squared-down front end is combined with a ratchet wheel.

Incense barrel lid

This refers to a cover that is attached to the barrel to prevent the spring from flying out of the barrel due to tension.


This is an engraving that is stamped on the base plate, rotor, etc. during the manufacturing process.

It is designed to identify the caliber number, manufacturer's name, number of jewels, etc.

In some cases, the Ref. No. and other information are engraved on the side of the case.

In addition, during aftercare, maintenance craftsmen may engrave dates or other information on the inside of the back cover.

Small Nails

It is designed to mesh with a ratchet wheel.

This prevents the mainspring from rotating backwards when wound.

It serves as a hook.

Complications Watch

The person who invented this was Breguet, a genius watchmaker.

This is the term used to describe a watch that has complicated functions.

Features include a perpetual calendar, minute repeater and tourbillon.

30 minute counter

This refers to the in-dial.

Used to measure 30 minutes after starting the chronograph.

Third wheel

This refers to the gear next to the second wheel.

This refers to the third gear that meshes from the barrel.


It is an abbreviation for Greenwich Mean Time.

This law was devised by Canadian railway engineer Stanford Fleming.

This refers to the global standard time established by the Greenwich Observatory based on the law that one rotation of the Earth takes 24 hours.


This is the common name for the Swiss Official Chronometer Testing Institute.

The headquarters is in Geneva.

An organization that tests the accuracy of watches and certifies them as chronometers.


This is the name given to the mechanism that winds the mainspring using arm movement, etc.

It uses a rotor that is built into the movement.

Based on a similar concept, some quartz watches also have their own power generating systems.

See Kinetic for more information.

12 hour clock

It's an in-dial.

This is the dial that measures 12 hours after the chronograph is started.

Geneva Stamp

It is certified by the City of Geneva.

It also serves as proof of high precision.

It is generally said to be ranked higher than chronometer certification.

This is an unconditional award given to Patek Philippe products.

Cylinder escapement

It was invented by the clockmaker George Graham in 1726.

It is a device that transmits the energy needed to make the balance wheel oscillate.

The escapement gear meshes with the cylindrical axis of rotation of the balance.

This device consists of a cylindrical part of the escape wheel and the balance wheel arbor.

It is no longer used due to its incomplete functionality.


It is written as Hz (Hertz).

It refers to the number of vibrations that occur per second.

The balance wheel, which rotates at a typical speed of 28,800 revolutions per hour, has a frequency of 8 vibrations (4 Hz).


This is the name given to Breitling's rotating scale, for example.

It can be found on the outside of the dial or on the bezel.

It is used for calculations and other purposes.


Recently, it has also been called see-through.

The internal structure is designed to be visible from both sides, with the base plate and bridges made transparent.

Split seconds

This is what the second chronograph hand is called.

The advantage is that two measurements can be performed simultaneously.

Typically, the split second hand moves together with the chronograph hand.

This means you can also measure lap times along the way.

If there are two runners, it is possible to measure both their times simultaneously using one watch.

Smooth balance

This refers to a balance wheel that is smooth and does not have a fine adjustment screw called a regulation screw.

Small seconds

A small hand that is independent of the hour and minute hands.

It is set in a sub-dial circle above the dial.

Sliding Gear

This is a device designed to prevent the 30-minute counter wheel and the chronograph runner's feed pawl from meshing together when resetting the chronograph.

Universal Time

See GMT.


It has an elapsed time display function.

It works together with starting the chronograph and displays the elapsed time.

Center Second

This is the second hand on the axis located in the center of the dial.

Center Minute Recording

It will calculate in one-minute increments.

This is a chronograph without a sub-dial.


It is the power source of a mechanical watch.

In the past, it was made of steel.

Around 1950, special steels such as Nivaflex, known as white mainsprings, began to be used.

Earthquake-resistant device

This device is installed to protect the central axis of the balance wheel, called the balance core, from impact.

The mechanism is such that the upper and lower stones are supported by the ground panel.

Tide Chrono

It is a chronograph equipped with a tide gauge.

It is used to measure the low and high tides.

This was developed for the people who work in ports.


This function is for measuring speed such as kilometres per hour.

It is printed and engraved on the chronograph bezel.

Its official name is "Taki Product Meter."


It is a device that converts the rotary motion generated by the energy of the mainspring into the regular reciprocating motion of the balance wheel.

It consists of an escape wheel and an anchor.

Main plate

It is the foundation of the movement.

The parts can be attached together with gears etc.

Adjustment screw

The balance wheel repeats a subtle oscillating motion, and this screw is installed to balance it.

Tsuzumi car

It was given this name because its shape resembles a drum, a musical instrument.

One end has angled teeth like a sawtooth.

And that is what makes it mesh with the crazy car.

On the other side is a gear called a sword-turning wheel, which has teeth that mesh with the gear to turn the hands to set the clock.


This word means using numbers.

A clock that can display the time using only numbers is called a digital clock.


This is the type where you wind the crown by hand.

This refers to a method of winding the mainspring by hand.


It is a chronograph that has the function of measuring the distance traveled during exercise.

The speed of sound travels is 340 meters per second.

This value is used for measurement.

First, a sound is played at location A, and then the distance to location B is measured.

This function is used to determine the distance between two locations.

Originally, this was a function used in the military.

Dot printing

This refers to the mechanism of the chronograph that was used in the very early days.

The dial itself rotates.

When the inked needle reached the appointed place, a simple movement raised the needle and made a mark on the dial.


This is what the escapement is called.

It is a regulating mechanism that controls the timepiece and is composed of a circular frame and a hairspring.

If we compare it to a wall clock, it functions like a pendulum.

It works to maintain rotational speed.

Balance cock

This refers to the bearing for the balance wheel.

This is equipped with a brake pedal and brake seat.

The temprature seat is also called the upper balance seat or the upper balance stone.


It was invented by an 18th century watchmaker named Bourguet.

This refers to the regulating device, and the aim was to improve accuracy.

The purpose was for the entire escapement to rotate at a set speed, averaging out the effects of gravity in all directions.


It is a radioactive substance.

It is applied to needles etc.

Rolex has traditionally placed the letter T on the dial.

Driving Wheel

These are the gears that transmit the power of the chronograph.

It moves on the same axis as the fourth wheel, which drives the small second hand.

Transmission Wheel

This is a gear that transmits the rotation of the driving wheel to the chronograph runner.


It is the American Aeronautics and Space Administration.

NASA Watch Test

This is a rigorous test carried out by NASA.

There were 11 tests, covering every conceivable environmental experiment in space.

There were various types, including those that could withstand high temperatures, low temperatures, high pressure, and impacts.

This test was conducted to select the official chronograph for use in the Apollo program.

Many famous manufacturers, including Rolex, attempted this NASA watch test with their chronographs, but the only one that passed with flying colors was the Omega Speedmaster.

Navigation Watch

See Aviation Watches.

Day difference

It indicates the gain or loss of a clock in one day.

Currently, the cesium atomic clock is said to have the smallest daily deviation.

Second wheel

This refers to the incense box.

This refers to the gear that meshes next to the first gear.

They are often designed to rotate once per hour.

Pilot's Watch

This refers to a watch developed for airline pilots.

The most common is the Breitling Navitimer.

This model comes with a built-in rotary slide rule that allows you to calculate fuel consumption.

In addition, Rolex's "GMT Master" series is a pilot watch equipped with a GMT function, and IWC's "Mark" series is designed to withstand the strong G-forces of fighter jets.

Parking Meter Chrono

This is a chronograph that is very suitable for measuring parking time.

The most famous ones are made by Paul Garnier.

When you press the reset button, the number in the small window will become zero.

If you press it again, the numbers will start rotating and count up to 60.

Heart-shaped cam

As the name suggests, it is a heart-shaped cam.

This part is used to reset the hands of counter dials such as the chronograph hands and 30-minute counter to zero.

Perpetual calendar

It refers to a perpetual calendar.

It is a mechanism that allows it to function without needing to be adjusted for a certain number of years.

It is programmed with the number of days in a month, the days of the week, leap years, etc.

Pallas Meter

It is a chronograph that measures your pulse rate.

The memory section has a standard measurement number written on it, such as 15 or 30.

It is used by medical professionals such as doctors and nurses.

Power Reserve Indicator

It is also called the Up-Down Indicator.

This is an indicator that shows the remaining winding of the mainspring.


This refers to the lever touching the reset button.

By using the force of a spring to strike the heart cam, the chronograph hands and other counters are reset to zero.

Hammer Spring

This is the pier that supports the hammer that touches the reset button.


This is a thin, hair-like spring that provides the power for the balance wheel to oscillate.

The speed at which the mainspring retracts is always constant, so this is utilized.

It is made of a material that is not easily affected by temperature.

Pillar Wheel

Due to the cost involved, it is now rarely seen.

This part converts the force applied to the chronograph lever into a rotating force.

It controls start, stop and reset.

This increases the accuracy of operation.

It also improves durability.


It is used in bicolor cases, etc.

It adds a touch of elegance to a stylish chronograph.

This refers to the fact that the bezels of current Breitling watches are a combination of gold and stainless steel.


Generally, there are two, one above and one below the crown.

This button is used to start, stop and reset the chronograph hands.


It is used to reset the chronograph hands to zero with one push.

And once you put it back, the system starts again without stopping.

Today, Zenith's El Primero "Rainbow Flyback" is a famous model.

Flat Beard

This is a part that was available in the early days.

It controls the frequency of the balance.

During rotation, the balance wheel and the center of the balance shaft do not coincide, resulting in a timing error.

Therefore, rolled hairs are now used, which solve these problems.


The main plate forms the base of the movement, but it is also the other part that receives the gear train mechanism.

Brake lever

When stopping the chronograph, it holds down the chronograph runner that has come off the transmission wheel.

Breguet Beard

This refers to the curled beard.

Production counting

It is useful for measuring large production quantities.

It is used to increase production efficiency.

It is a chronograph that counts the number of products produced within a set period of time.


This refers to the edge around the glass.

Baby Chrono

This refers to a miniature chronograph made by Rolex that was made before the Daytona.

It has become a collector's item and is rarely seen on the market.


This refers to the gears in a clock movement.

Waterproof function

This indicates the air pressure at which the waterproofing can be withstood.

Walking speed

This refers to the pace at which a clock gains or loses speed.

When converted into a daily value, it is called the daily difference.

When converted to a monthly amount, it is called the monthly difference.


It was developed by Heuer in 1916.

It has also been patented as a chronograph capable of measuring to 1/100th of a second.

In 1882, the company became the first manufacturer to start mass-producing chronographs.

Then in 1887, they developed a part called the "oscillating pinion," which was adopted in chronographs by major manufacturers.

An extension of this is the micrograph.

Micro Module

This refers to a high-performance time adjusting device that serves as a regulator.

Micro Rotor

This refers to an automatic winding rotor that is installed away from the center axis of the movement.

Winding stem

The winding stem turns together with the crown, causing the winding wheel to turn.

When the Tsuzumi wheel turns, the Kichi wheel turns.

The mainspring is wound when the gear wheel and the crown wheel mesh together.

Round hole wheel

It meshes with the timing wheel and rotates when the spring is wound, causing the ratchet wheel to turn.

Minute Recording Wheel

This refers to the gears that make up the 30-minute counter.

Minute Recording Intermediate Wheel

It is the gear at the end of the sliding gear.

It is responsible for transmitting the rotation of the chronograph runner to the gear of the 30-minute counter.


This refers to the internal mechanism that powers the watch.


It is one of NASA's standard equipment.

The OMEGA Speedmaster was the watch that supported the first manned landing on the moon.

This is what I am referring to.

It was born in 1957 and went on sale the following year in 1958.

This is a hand-wound model, and from 1966 onwards the word "Professional" was written on the dial.

Moon Phase

This function displays the age of the moon, also known as the phase of the moon.

They were so named because they represent the aspects, or phases, of the moon.

It is considered a complex function.

Memento Dial

This refers to a dial that is not related to the main body.

Universal holds the patent for the Memento Dial.

The user manually records the specified time on this dial.

Yachting Chrono

The 30-minute counter on the in-dial is divided into six sections, each with five-minute increments, to improve visibility.

During a yacht race, a warning pistol is fired five minutes before the start.

So it was developed to accommodate that.

This model was developed for competitive yacht sailors.

Fourth wheel

As the name suggests, it is the fourth gear from the barrel.

The second hand is often attached to the axis of this gear.

In the small second type, it is located at 6 or 9 o'clock.

It rotates once per minute.


This refers to radioactive materials.

It was previously used as a luminous paint for indexes and other parts.

It was previously used in watches such as the Radiomir developed by Panerai.


This is a part used when winding the mainspring and setting the time.

It is equipped at the end of the winding stem.

It is said that the name was given to this area because it resembles a dragon's head.


This was the world's first pocket watch chronograph, produced by Longines.

It was first sold in 1879.

It was equipped with a stopwatch function with a second hand.


It is a highly safe, non-radioactive material.

It is now used as a substitute for radium, coating indexes and other parts.

This is the successor to the Panerai Radiomir.

This is also the origin of the name "Luminol," which has been revived and is very popular.


It is a rotating weight.

It is an automatic movement, and is used to generate power to wind the mainspring.

They are generally made of stainless steel, but sometimes gold is used.